The sensitivity of the HPV test for detecting cervical cancer and its precursor lesions has been reported to be far higher than Pap smear test, and it is now recommended for use in “cotesting” with Pap smear test in some parts. Accordingly, the accuracy analysis followed by the quality control of each HPV test are demanded for the appropriate diagnosis and treatment. This study was carried out to compare the performance of HPV DNA chip test, real time PCR HPV test and Hybrid capture II test in ASCUS population.
We performed HPV DNA chip test, real time PCR HPV test and Hybrid capture II test in 504 cervical swab samples of ASCUS patients diagnosed in 5 hospitals, from February 2012 to August 2014. The concordance rates between the three tests, including those detecting HPV 16 or 18 in case of HPV DNA chip test and real time PCR HPV test, finally the result of sole discrepancy of each test were analyzed.
The concordance rate between real time PCR HPV test (PCR) and Hybrid capture II test (HCII) was 86.3%, HPV DNA chip test (Chip) and HCII was 84.9%. In terms of detecting HPV 16 or 18, the concordance rate between PCR and Chip was 97.2%, however, overall concordance rate of identifying the existence of HPV between above two tests was 79.2%, and slightly higher to 80.8% when only high risk HPV types were categorized as positive result in Chip. On analysis of only Chip negative results (n=62), when negative was defined as the absence of high risk types, 67.7% (42/62) of the cases were “other” types on Chip. On the other hand, 50% (10/20) of the cases where PCR showed sole negative result (n=20), Chip-detected HPV types were either HPV 68 (n=8) or HPV 58 (n=2). The other half of PCR-undetected HPV types were those not included in the test system. There was only one case where HCII showed sole negative result, and among 35 cases of HCII sole positive result, 65.7% (23/35) were in HCII RLU/CO level gray zone (1~10).
HPV DNA chip test may be as accurate as real time PCR HPV test when detecting HPV 16 or 18, which accounts for approximately 70% of all invasive cervical cancer. However, when the result of HPV DNA chip test shows HPV other types, subsequent meticulous observation or trial of different HPV test are of concern, as the sole discrepancy may be numerous. Additionally, it would worth to keep in mind that real time PCR test is vulnerable in detecting HPV 68 or 58. Finally, careful interpretation would be required for those of the results in RLU/CO level gray zone in Hybrid capture II test.